This invention relates in general to apparatus for pumping controlled quantities of fluid through a closed fluid system, and is more particularly concerned with a cassette for incorporation into an administration set for accurately metering the volume of parenteral fluid flowing through the administration set, and with a controller for controlling fluid flow through the cassette.
In recent years, the need has arisen for apparatus for controlling the rate of administration of parenteral fluids to a patient with a high degree of accuracy while maintaining a closed fluid system to avoid the possibility of contamination of the infused fluids.
One type of apparatus utilized for accurately metering fluid flow in a closed system utilizes a cassette-type pump element included as an integral component of the flow system, together with a controller mechanism which actuates the pump element at a predetermined rate to establish a desired flow rate within the system. After use, the cassette element is disengaged from the controller mechanism, and discarded with the flow system, thereby avoiding the possibility of contamination of subsequently administered liquids.
The present invention is directed to a cassette and controller which provides improved metering accuracy, and which can be economically manufactured by known manufacturing techniques.